Bird flu (avian influenza) is an infection with strains of influenza that normally occur in wild birds and sometimes pigs.
Bird flu is caused by several strains of influenza A that normally infect wild birds. The infection can be easily spread to domestic birds and sometimes pigs. However, it rarely spreads from animals to people. Most people who have been infected with bird flu have had close contact with an infected bird. Human infection with the avian flu strain H5N1 first occurred in Hong Kong, then in Vietnam, Indonesia, Cambodia, China, Thailand, Turkey, Azerbaijan, Djibouti, Egypt, and Iraq. There have been 230 cases between 2003 and the middle of 2006. Other strains of avian influenza have caused eye infections (conjunctivitis) and respiratory disorders in poultry workers in Canada and the Netherlands.
People infected with the current strain of bird flu (H5N1) cannot spread the infection to other people. Experts are concerned mainly that the genetic material of the virus could change (mutate) and enable the virus to spread from person to person. Then, bird flu could spread rapidly and widely, causing a major worldwide epidemic (pandemic).
Symptoms vary depending on which strain of the virus is the cause. People may have extreme difficulty breathing and flu-like symptoms (such as fever, cough, sore throat, and muscle aches). Some people have conjunctivitis or pneumonia. The risk of death has been high: 30% in one outbreak and almost 80% in another.
People who have flu-like symptoms and have had contact with birds in an area where birds are known to carry the infection should contact a doctor. The doctor can send a nose or throat swab to be tested.
Spread is contained by identifying and destroying infected flocks of domestic birds. A vaccine for bird flu is being developed.